Steps for replacing water heater systems and identifying a failing water heater

The basics for replacing water heater tanks are simple and inexpensive if you do it yourself.

You can save hundreds of dollars in labor by doing a water heater replacement or new installation without an Electrician. It only takes about an hour to do everything.

The most important thing about replacing an electric water heater is electrical safety. Electric water heaters use 240-volt circuits. These are the bad boys that deserve complete respect. Be sure to turn off the breaker and communicate to household members what you are doing.

replace electric water heater
The question about replacing water heaters that I get most often is, “should I repair my water heater or replace it?”

The answer is pretty simple. If the water heater is more than 10 years old, you should probably replace it. Electric water heaters are notorious for running up really high electric bills when they are failing. Last week, I replaced my electric water heater because the hot water supply had diminished to about one-third the normal hot water supply.

Also, my electric bill was at least twice as high as normal. Failing electric water heaters have to compensate for hot water inefficiency by using more power to produce the same output as normal.

The $300 price tag of a new water heater looked pretty attractive considering my electric bills were around $200 a month higher than normal.

The decision to replace was very easy to make.

At this point, you need to shop around for the best water heater within your budget. You will need to make sure the new water heater is similar to the one you’re replacing. If you are replacing a 50-gallon water heater, you will probably want at least that same size.

Also, make sure that the fittings on the top of the new tank are compatible with the water lines that feed into the tank. Most of these are a standard size. Be sure that the new tank will fit into the same space as the old water heater.

You might need new flexible copper tubing if the new tank is longer or shorter than the old one. These fittings are available where the water heaters are.

water heater breaker
Most electric water heaters are on a 240-volt, 30-amp breaker. Make sure this breaker is the correct water heater breaker and that it is turned off.

test electric circuit
In addition to making sure the breaker is turned off, I always test the circuit for current. A circuit tester only costs around $4. It’s a good item to have around.

If the tester light is on, there is still current in the line and it is probably a lot of current.

If the light is off, the line is dead. That’s always a good sign before working on the wiring. Safety is key when replacing water heater tanks.

Once you are certain the electricity is off, you can take the wiring apart. The wires will be two cables usually a black and a red wire. There will usually be a copper ground wire also.

water heater shutoff
Once you have the new water heater ready to put in, you will start removing the old water heater by first shutting off the water input line. If you don’t have a local shutoff valve at the water heater supply line, you will need to turn off the water main line to your home.

water heater drain
Once the water supply line has been shut off, you can start to drain the old tank. You can do this with a garden hose. Be sure to run the hose outside or to a drain that is safe. The water will be very hot and the risk of scalding is high if someone comes in contact with it.

Once the tank is completely drained, you can disconnect both copper water lines with a pipe wrench. You will also need to disconnect the relief valve tubing.

Remove the old tank and then put the new tank in place. Wrap the threads of the new tank supply nipples with teflon tape. One layer of teflon tape will prevent leaks.

Attach the cold water input line to the cold water intake nipple. This will usually have a blue color around it. Attach the water line that will service all hot water appliances to the red colored nipple.

Make sure that both connections are really tight.

Next connect the relief valve.

Once all connections are tight, you will open the water input shutoff valve to start filling the new tank. It’s import to help release the air from the tank as it fills by opening the hot valve of a few faucets around the house. This will let the air in the tank escape as the air releases from the faucets.

Once the faucets are running water in a complete stream from the hot valves, the water heater tank should be full of water.

Verify that there are no leaks around the connections after replacing-water-heater tank fixtures.

water heater wiring
Connect the wiring to the wiring of the water heater according to the instructions with the heater. Make sure to get a good connection with the wires in the wire nut.

Replace the cover to the wires and turn the breaker back on. That is all you need to do when replacing-water-heater tanks by yourself.

top of page

Over 4 million visitors to this site since it was born!

My newsletter keeps you up to date on home construction and design ideas.

home construction

I just wanted to say that I love your website. My husband and I followed your instructions on building our own home. Most of the work we did ourselves, but not all. We saved $90,000 in labor costs and now have a beautiful home that we own.

--Sue and Les Carrigan, Draper, Utah

I built my own home doing all my own labor. My house costs me around $70,000 for materials. It took me 8 months to build and is about 2,000 square feet. I didn't think I could do it, but your house web site encouraged me. I used all the info you had.

Thank you,

Benny Luis Lopez,

Gainsville, Florida

I can't thank you enough for your free information web site about home building. I was looking for Electrical wiring diagrams when I found your site. It was very helpful.

Steve Lundquist,

Little Rock, Arkansas

My wife and I lost our home to foreclosure but we kept a plot of land to start over. We are halfway through the construction of our house. Your website gave us hope to start over and build a house with low payments. We are in our late 60's but we find it rewarding to put so much effort into a project that will reward us for years to come.

Name respectfully withheld